This invention relates generally to bicycles and more particularly to an adjustable stem for use on bicycles. The stem that is employed as a common component of bicycles serves to connect the handlebar to the bicycle frame itself. In prior art bicycles, the stem holds the handlebar in a fixed position with respect to the frame of the bicycle. A fixed position stem and, hence, handlebar, is not at all suitable for all riders under all riding conditions. For example, maintaining the body position required by a fixed position stem may be uncomfortable to the point of painfully straining the rider's back during the course of a long ride. Fixed position stems are also disadvantageous in that they force cyclists to make one choice of stem to fit all riding conditions, such as uphill, downhill, fresh at the beginning of the day, and fatigued at the end of the day. This is much like asking a golfer to select a single club with which to play an entire round of golf.
Some bicycle manufacturers have made an attempt to minimize the problems presented by fixed position stems by offering different fixed position stems on different bicycle models. For example, a very upright stem may be offered on models used by beginners, while a very forward stem may be offered on models targeted for agressive or expert riders. However, even these different fixed position stems offered as a function of the bicycle model purchased are disadvantageous in that they first force a bicycle purchaser to choose between an aggressive bicycle and a strictly recreational bicycle at the time of purchase. After he has purchased such a bicycle, the rider is forced to accept the particular fixed position stem, with which his bicycle is equipped, under all types of riding conditions.
It is therefore the principal object of the present invention to provide an adjustable bicycle stem that permits the rider to adjust the position of the handlebar, while riding, to accommodate a variety of terrain conditions that may be encountered, as well as his physical condition at any time.
This and other incidental objects are accomplished in accordance with the illustrated preferred embodiment of the present invention by providing a bicycle stem having a downwardly projecting member adapted for insertion into a conventional receptacle in the frame of a bicycle and an adjustable forwardly projecting member adapted to hold the bicycle handlebar. The downwardly and forwardly projecting members of the stem are coupled for rotational adjustment of the forwardly projecting member with respect to the downwardly projecting member by providing a toothed adjustment plate and engaging pin arrangement by which the rider may incrementally raise or lower the handlebar, even while riding.